Dad just traded off a 2019 with almost exactly 100k on it. It's had the timing chain rattle since about 25k on cold start, blew the transmission at 40k, never shifted right from day one, hard up and down shifts for the past 30k or so. He got rid of it right as the warranty expired. All in all, if he had to pay for all the repairs and the work it needed over the course of his ownership, it would've been about $10-15,000. By far, the most unreliable vehicle he ever owned. I had a 2015 that had 10 grand worth of work in the 7 months I owned it, between 62,000 miles and 68,000. No hot rodding or anything, just commuting. But you didn't ask about the 2015, so I'll digress there.
Grandparents had their newer (unsure of the year) ecoboost expedition catch fire getting on the freeway last fall. No warning, no perceivable reason, just flames from under the hood. Even the mechanic that was hired by the insurance company couldn't track down a cause. They had the cold start rattle from time to time, but never thought anything of it.
All 3 of those examples were the 3.5l variety. A Honda Pilot uses a 3.5l engine, and throwing some turbos on it doesn't make it a towing machine. At the end of the day, you're asking a crossover engine to do the work of a big block V8. You're asking for trouble, and that's speaking from experience.
The 5.0 is notorious for wearing cylinders out of round between 100/120k and losing compression. Ford has struggled with gas engines since the late 90's with the advent of the 5.4 (talk about a train wreck), and with diesels since 2003.5 when they came out with the 6.BLOW.
We used to be dyed-in-the-wool Ford fans, through and through. Now, there's not a blue oval anywhere to be seen. Personally, I wouldn't buy either one of them, unless the dealer is throwing in a bumper to bumper warranty on their dime, and even then, I would dump it as quick as the warranty is about to expire.
EDIT TO ADD: You say your number one priority is long-term reliability and maintenance costs. If that's the case, why on earth aren't you looking at a Toyota Tundra?